CAJ | 학술논문

利用草酸作为浸出剂以除去拜耳法残渣赤泥中的氧化铁,从而提高赤泥的工业应用价值,同时对草酸浸出液进行紫外光照射,将草酸铁还原成草酸亚铁沉淀,实现草酸溶液循环再利用.实验结果表明,在75℃下,赤泥在1 mol/L草酸溶液中浸出2h,氧化铁的浸出率可达到96％,浸出后赤泥中氧化铁的含量由17.6％降低至小于1％.在紫外光照催化作用下,1h内浸出液中90％以上的草酸铁转变成草酸亚铁沉淀,剩余草酸可循环再利用.该草酸亚铁为β-FeC2O4·2H2O.对UV催化沉淀的机理进行讨论分析.
이용초산작위침출제이제거배이법잔사적니중적양화철,종이제고적니적공업응용개치,동시대초산침출액진행자외광조사,장초산철환원성초산아철침정,실현초산용액순배재이용.실험결과표명,재75℃하,적니재1 mol/L초산용액중침출2h,양화철적침출솔가체도96％,침출후적니중양화철적함량유17.6％강저지소우1％.재자외광조최화작용하,1h내침출액중90％이상적초산철전변성초산아철침정,잉여초산가순배재이용.해초산아철위β-FeC2O4·2H2O.대UV최화침정적궤리진행토론분석.
Red-mud is the residue from the Bayer process,in which the iron minerals should be removed before red-mud is used to produce refractory materials.The iron minerals in red-mud were extracted by oxalic acid solution.The content of Fe (calculated in Fe2O3) in red-mud was reduced from 17.6％ to less than 1％ after being treated by 1 mol/L oxalic acid solution at 75 ℃ for 2 h.The Fe(Ⅲ) oxalate solution obtained was then irradiated by UV light,resulting in the precipitation of Fe(Ⅱ) oxalate.Under UV photocatalysis,more than 90％ of Fe(Ⅲ) oxalate in the extracted solution was transformed into the precipitation of Fe(Ⅱ) oxalate crystallite (β-FeC2O4·2H2O).The filtrate from the Fe(Ⅱ) oxalate precipitate filtration could be reused in the next cycle.The mechanism of UV photocatalysis precipitation was also discussed.